Method and apparatus for firearm recoil simulation

ABSTRACT

A method and apparatus for firearm training simulator which simulates realistic recoil of conventional firearms. The method and apparatus incorporates a linear motor and controllable mass for generating recoil. One embodiment includes an adjusting system for adjusting the amount of recoil provided. Also provided are means for simulating semiautomatic and/or full automatic operation of firearms. One embodiment can include a laser emitter which simulates the path for a bullet fired from a firearm that the method and apparatus is simulating.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/486,443, filed Apr. 13, 2017, which is a continuation of U.S. patentapplication Ser. No. 14/808,247, filed Jul. 24, 2015, now U.S. Pat. No.9,810,502, which is a continuation of Ser. No. 13/804,429, filed Mar.14, 2013, now U.S. Pat. No. 9,146,069, which claims the benefit of U.S.Provisional Patent Application No. 61/650,006, filed May 22, 2012, eachof which are incorporated herein in their entirety by reference thereto.

BACKGROUND

One embodiment relates to simulating of recoil for firearms. Morespecifically, one embodiment provides a method and apparatus forsimulating the recoil of a selected conventional firearm. One embodimentadditionally provides a laser to simulate the path of a bullet if thebullet had been fired from a firearm being simulated by the method andapparatus.

Firearms training for military personnel, law enforcement officers, andprivate citizens increasingly encompass role playing and decision makingin addition to marksmanship. Such training often includes competingagainst role players and/or responding to situations projected onto ascreen in front of the trainee.

Although self-healing screens exist, permitting the use of conventionalfirearms for such training, the use of such a system requires a locationappropriate to the use of conventional firearms. Furthermore, suchsystems are expensive and can be unreliable. Alternatives toconventional firearms have been developed. These alternatives includepaintball, simunitions, and the use of a laser to show the path a bulletwould have taken had one been fired.

Such alternatives, however, do not duplicate substantially all of thecharacteristics of firing an actual weapon with actual ammunition, andthe current alternatives limit the extent to which the training willcarry over to use of actual firearms. In various embodiments thecharacteristics of a conventional firearm to be duplicated can includesize, weight, grip configuration, trigger reach, trigger pull weight,type of sights, level of accuracy, method of reloading, method ofoperation, location and operation of controls, and recoil.

Realistic recoil is the most difficult characteristic to duplicate. Theinability to get a trainee accustomed to the recoil generated by aparticular firearm is one of the greatest disadvantages in the use ofvarious firearm training simulators. Recoil not only forces the firearmshooter to reacquire the sights after shooting, but also forces theshooter to adapt to a level of discomfort proportional to the energy ofthe particular bullet to be fired by the firearm. Recoil issignificantly more difficult to control during full automatic fire thanduring semi-automatic fire, making the accurate simulation of bothrecoil and cyclic rate important in ensuring that simulation trainingcarries over to the use of actual firearms.

While certain novel features of this invention shown and described beloware pointed out in the annexed claims, the invention is not intended tobe limited to the details specified, since a person of ordinary skill inthe relevant art will understand that various omissions, modifications,substitutions and changes in the forms and details of the deviceillustrated and in its operation may be made without departing in anyway from the spirit of the present invention. No feature of theinvention is critical or essential unless it is expressly stated asbeing “critical” or “essential.”

SUMMARY

One embodiment provides a firearm training simulator having a recoilemulating the recoil impulse pattern of a particular firearm firing aparticular size and type of bullet. In one embodiment the method andapparatus can include a laser beam projector for projecting the path ofa bullet fired from the particular firearm being simulated.

In various embodiments the method and apparatus can also simulateadditional operations of a particular firearm which operations includesighting, positioning of the firearm controls, and methods of operationof the firearm. Particular firearms that can be simulated include M-4A1,AR-15, or M-16 rifles, along with other conventional firearms.

In one embodiment the method and apparatus can be controlled by acombination of the trigger assembly, bolt, and linear motor. In variousembodiments the method and apparatus is capable of simulating modes ofsemi-automatic fire and full automatic firing. In various embodimentsthe cyclic rate of full automatic firing mode simulation issubstantially the same cyclic rate of a conventional automatic rifle.

One embodiment provides a laser substantially tracking the path of anactual bullet being fired from a firearm being simulated. One laseremitter can be housed within the barrel of the firearm simulating body.In one embodiment the laser emitter can be operatively connected to acontroller which is also operatively connected to a recoil. Oneembodiment of the switch may be a roller switch structured to beactuated by a switching rod extending forward from the bolt. When thebolt moves forward in response to pulling the trigger, the switching rodengages the roller of the switch, thereby depressing the switch andactuating the laser. Another embodiment uses a proximity switch mountedin a location wherein a magnet may be brought into contact with it uponforward movement of the bolt. A preferred location is adjacent to thejuncture between a barrel and upper receiver. A magnet affixed to thebolt is structured to be brought into proximity with the proximityswitch when the bolt is in its forwardmost position, thereby causing theproximity switch to actuate the laser.

One embodiment provides a method and apparatus wherein the level ofrecoil imparted to the user may be programmed by the user.

One embodiment provides a method and apparatus capable of bothsemi-automatic and full automatic operation.

One embodiment provides a method and apparatus wherein different cyclicrate of full automatic fire may be programmed by the user.

One embodiment provides a method and apparatus including a laserassembly projecting laser substantially along the path of a bullet thatwould have been fired from the firearm being simulated.

One embodiment provides a method and apparatus simulating the recoil ofa conventional firearm using a linear motor controlling a sliding massand operatively coupled to a controller.

A linear motor can be thought of as an electric motor that has had itsstator and rotor “unrolled” so that, instead of producing a torque(i.e., through rotation), it produces a linear force along itslongitudinal length. The most common mode of operation for conventionallinear motors is as a Lorentz-type actuator, in which the applied forceis linearly proportional to the current and the magnetic field.

Many designs have been put forward for linear motors, falling into twomajor categories, low-acceleration and high-acceleration linear motors.Low-acceleration linear motors are suitable for maglev trains and otherground-based transportation applications. High-acceleration linearmotors are normally rather short, and are designed to accelerate anobject to a very high speed, for example see the railgun. They areusually used for studies of hypervelocity collisions, as weapons, or asmass drivers for spacecraft propulsion. The high-acceleration motors areusually of the AC linear induction motor (LIM) design with an activethree-phase winding on one side of the air-gap and a passive conductorplate on the other side. However, the direct current homopolar linearmotor railgun is another high acceleration linear motor design. Thelow-acceleration, high speed and high power motors are usually of thelinear synchronous motor (LSM) design, with an active winding on oneside of the air-gap and an array of alternate-pole magnets on the otherside. These magnets can be permanent magnets or energized magnets. TheTransrapid Shanghai motor is an LSM.

Linear motors employ a direct electromagnetic principle. Electromagneticforce provides direct linear movement without the use of cams, gears,belts, or other mechanical devices. The motor consists of only twoparts: the slider and the stator. The slider is a precision assemblythat consists of a stainless steel tube, which is filled with neodymiummagnets, that has threaded attachment holes on each end. The stator,consisting of coils, the bearing for the slider, position sensors and amicroprocessor board, is designed for use in harsh industrialenvironments.

A solenoid is a coil wound into a tightly packed helix. The termsolenoid refers to a long, thin loop of wire, often wrapped around ametallic core, which produces a magnetic field when an electric currentis passed through it. The term solenoid refers specifically to a coildesigned to produce a uniform magnetic field in a volume of space (wheresome experiment might be carried out). In engineering, the term solenoidmay also refer to a variety of transducer devices that convert energyinto linear motion. The term is also often used to refer to a solenoidvalve, which is an integrated device containing an electromechanicalsolenoid which actuates either a pneumatic or hydraulic valve, or asolenoid switch, which is a specific type of relay that internally usesan electromechanical solenoid to operate an electrical switch; forexample, an automobile starter solenoid, or a linear solenoid, which isan electromechanical solenoid.

Electromechanical solenoids consist of an electromagnetically inductivecoil, wound around a movable steel or iron slug (termed the armature).The coil is shaped such that the armature can be moved in and out of thecenter, altering the coil's inductance and thereby becoming anelectromagnet. The armature is used to provide a mechanical force tosome mechanism (such as controlling a pneumatic valve). Althoughtypically weak over anything but very short distances, solenoids may becontrolled directly by a controller circuit, and thus have very lowreaction times. The force applied to the armature is proportional to thechange in inductance of the coil with respect to the change in positionof the armature, and the current flowing through the coil (see Faraday'slaw of induction). The force applied to the armature will always movethe armature in a direction that increases the coil's inductance. Thearmature is a ferromagnetic material. Free recoil is a vernacular termor jargon for recoil energy of a firearm not supported from behind. Freerecoil denotes the translational kinetic energy (E_(t)) imparted to theshooter of a small arm when discharged and is expressed in joule(J) andfoot-pound force (ft·lbf) for non-SI units of measure. More generally,the term refers to the recoil of a free-standing firearm, in contrast toa firearm securely bolted to or braced by a massive mount or wall.

Free recoil should not be confused with recoil. Free recoil is the givenname for the translational kinetic energy transmitted from a small armto a shooter. Recoil is a name given for conservation of momentum as itgenerally applies to an everyday event.

Free recoil, sometimes called recoil energy, is a byproduct of thepropulsive force from the powder charge held within a firearm chamber(metallic cartridge firearm) or breech (black powder firearm). Thephysical event of free recoil occurs when a powder charge is detonatedwithin a firearm, resulting in the conversion of chemical energy heldwithin the powder charge into thermodynamic energy. This energy is thentransferred to the base of the bullet and to the rear of the cartridgeor breech, propelling the firearm rearward into the shooter while theprojectile is propelled forward down the barrel, with increasingvelocity, to the muzzle. The rearward energy of the firearm is the freerecoil and the forward energy of the bullet is the muzzle energy.

The concept of free recoil comes from the tolerability of gross recoilenergy. Trying to figure the net recoil energy of a firearm (also knownas felt recoil) is a futile endeavor. Even if you can calculate therecoil energy loss due to: muzzle brake; recoil operated action or gasoperated action; mercury recoil suppression tube; recoil reducing buttpad and or hand grip; shooting vest and or gloves, the human factor isnot calculable.

Free recoil can be thought of as a scientific measurement of recoilenergy. The comfort level of a shooter's ability to tolerate free recoilis a personal perception. Just as it is a person's, personal perceptionof how comfortable he or she feels to room or outside temperature.

There are many factors that determine how a shooter will perceive thefree recoil of his or her small arm. Some of the factors are, but notlimited to: body mass; body frame; experience; shooting position; recoilsuppression equipment; small arm fit and or environmental stressors.

There are several different ways to calculate free recoil. However, thetwo most common are the momentum short and long forms.

Both forms will yield the same value. The short form uses one equationas where the long form requires two equations. With the long form youwill first find for the fire arm velocity. With the velocity known forthe small arm, the free recoil of the small arm can be calculated usingthe translational kinetic energy equation. A calculation can be done asfollows:

Momentum Short Form:

E _(tgu)=0.5*m _(gu)*[[(m _(p) *v _(p))*(m _(c) *v _(c))]/1000]² /m_(gu) ²

Momentum Long Form:

v _(gu)=[(m _(p) *v _(p))+(m _(c) *v _(c))]/(1000*m _(gu)) and

and

E _(tgu)=0.5*m _(gu) *v _(gu) ²

-   Where as:    -   E_(tgu) is the translational kinetic energy of the small arm as        expressed by the joule (J).    -   m_(gu) is the weight of the small arm expressed in kilograms        (kg).    -   m_(p) is the weight of the projectile expressed in grams (g).    -   m_(c) is the weight of the powder charge expressed in grams (g).    -   v_(gu) is the velocity of the small arm expressed in meters per        second (m/s).    -   v_(p) is the velocity of the projectile expressed in meters per        second (m/s).    -   v_(c) is the velocity of the powder charge expressed in meters        per second (m/s).    -   1000 is the conversion factor to set the equation equal to        kilograms.

In various embodiments the linear motor comprises a sliding mass/rodincluding a plurality of individual magnets each having north and southpoles. In various embodiment the plurality of individual magnets arelongitudinally aligned with like poles of adjacent magnets facing likepoles. In various embodiment the plurality of individual magnets arelongitudinally aligned with unlike poles of adjacent magnets facingunlike poles. In various embodiments the plurality of individual magnetsin the sliding mass/rod comprise 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14, 15, 16, 19, 20, 25, 30, 35, 40, 45, and/or 50 magnets. In variousembodiments the number of magnets is between the range of any two of theabove listed numbers.

In various embodiments the linear motor includes a plurality of magneticcoils independently controllable with respect to each other regardingtiming and/or amount of current flow. In various embodiments theplurality of independently controllable magnetic coils are eachindependently controllable regarding the timing and/or amount of currentflow and/or direction of current flow.

In various embodiments each of the plurality of independentlycontrollable magnetic coils can include a plurality of sub-coil sectionsthat are spaced apart from each other but connected electrically inseries causing the electrically serially connected spaced apart sub-coilsections to form a single independently controllable magnetic coil. Invarious embodiments at least one sub-coil of a first independentlycontrollable magnetic coil of the plurality of coils is intermediatelyspaced between two spaced apart sub-coils of a second independentlycontrollable magnetic coil of the plurality of coils. In variousembodiments the linear motor comprises a plurality of independentlycontrollable magnetic coils which are longitudinally aligned with eachother and closely spaced, wherein at least two adjacent independentlycontrollable magnetic coils are energized to create oppositely polarizedmagnetic fields. In various embodiments the linear motor comprises aplurality of independently controllable magnetic coils which arelongitudinally aligned, wherein adjacent independently controllablemagnetic coils are simultaneously energized to create oppositelypolarized magnetic fields.

In various embodiments the linear motor comprises a plurality ofindependently controllable magnetic coils which are longitudinallyaligned with each other and closely spaced, slidingly connected to asliding mass of magnets which sliding mass is comprised of a pluralityof longitudinally aligned adjacent magnets, wherein the linear motorcauses movement of a sliding mass of magnets by varying current throughindividual independently controllable coils in relation to the proximityof a particular magnet in the plurality of magnets to a particular coilin the plurality of independently controllable magnetic coils.

In various embodiments the plurality of individually controllablemagnetic coils in the plurality of coils include at least 2, 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 19, 20, 25, 30, 35, 40, 45, and/or50 independently controllable coils. In various embodiments the numberof independently controllable magnetic coils is between the range of anytwo of the above listed numbers.

These together with other objects of the invention, along with thevarious features of novelty which characterize the invention, arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and the specific objects attained by its uses,reference should be made to the accompanying drawings and descriptivematter in which there are illustrated preferred embodiments of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and objects other than those setforth above will become apparent when consideration is given to thefollowing detailed description thereof. Such description makes referenceto the annexed drawings wherein:

FIG. 1 is a side view of one embodiment of a firearm training system.

FIG. 2 is a side view of simulated firearm body of the system shown inFIG. 1.

FIG. 3 is a perspective view of the upper assembly of the simulatedfirearm body of FIG. 2.

FIG. 4 is an exploded view of the simulated firearm body of FIG. 2.

FIG. 5 is a perspective view of one embodiment of a linear motor andsliding mass.

FIG. 6 is an exploded side view of one embodiment of a linear motor andsliding mass.

FIG. 7 is an assembled side view of the linear motor and sliding mass ofFIG. 6.

FIG. 8 is a perspective view of one embodiment of a support bracket forthe linear motor and sliding mass.

FIG. 9 is a side view of one embodiment of a simulated firearm body.

FIG. 10 is a schematic flow diagram of various operation of thesimulated firearm system shown in FIG. 1.

FIG. 11 is a sequencing side view showing the sliding mass of the linearmotor at an initial position relative to simulated firearm body in asimulation recoil cycle.

FIG. 12 is a sequencing side view showing the sliding mass of the linearmotor extending the sliding shaft to the end of its rightmost movementrelative to simulated firearm body in a simulation recoil cycle.

FIG. 13 is a sequencing side view showing the linear motor retractingthe sliding mass relative to simulated firearm body in a simulationrecoil cycle.

FIG. 14 is a sequencing side view showing the linear motor continuing toretract the sliding mass relative to simulated firearm body in asimulation recoil cycle.

FIG. 15 is a sequencing side view showing the linear motor afterfinishing the retraction of the sliding mass relative to simulatedfirearm body in a simulation recoil cycle so that the linear motor isready for the next simulation recoil cycle.

FIG. 16 is a prophetic graph plotting recoil force versus time of afirst round of ammunition along with force versus time caused by thelinear motor kinematically controlling dynamics of the sliding mass.

FIG. 17 is a prophetic graph plotting recoil force versus time of asecond round of ammunition along with force versus time caused by thelinear motor kinematically controlling dynamics of the sliding mass.

FIGS. 18-21 are schematic sequencing diagrams illustrating an individualrepetitively firing of a firearm with recoil causing increasing loss ofaccuracy with repetitive shots.

FIG. 22 is a perspective view of another embodiment of a linear motorand sliding mass.

FIG. 23 is a perspective view of a sliding mass with exemplary magnetsremoved.

FIG. 24 is an enlarged perspective view of the sliding mass withexemplary magnets.

FIG. 25 is a schematic diagram illustrating operation of the coils in alinear motor.

FIGS. 26 and 27 are schematic diagrams illustrating operation of thecoils in a linear motor in two different energized states.

FIGS. 28 and 29 are schematic diagrams illustrating movement of magnetsthrough a linear motor in two different energized states.

FIG. 30 is a diagram illustrating magnetic flux density versus voltageoutput.

FIGS. 31 and 32 are exemplar diagrams of sensor voltage response versustime for a slider moving through the linear motor.

FIG. 33 is a diagram of a sample wave form.

FIGS. 34 and 35 are exemplar diagrams of sensor voltage response versustime for a slider moving through the linear motor at two differentconstant linear speeds.

FIG. 36 is an exemplar diagrams of a force versus time plotted forrecoil forces for an actual firearm, compared to simulated recoil forcesby the method and apparatus using a mechanical stop, and not using amechanical stop.

FIG. 37 is an exemplar diagrams of an acceleration versus time plottedfor recoil acceleration for an actual firearm, compared to simulatedacceleration of the sliding mass caused by the method and apparatususing a mechanical stop, and not using a mechanical stop.

FIG. 38 is an exemplar diagrams of a velocity versus time plotted forrecoil velocity for an actual firearm, compared to simulated velocity ofthe sliding mass caused by the method and apparatus using a mechanicalstop, and not using a mechanical stop.

DETAILED DESCRIPTION

Detailed descriptions of one or more preferred embodiments are providedherein. It is to be understood, however, that the present invention maybe embodied in various forms. Therefore, specific details disclosedherein are not to be interpreted as limiting, but rather as a basis forthe claims and as a representative basis for teaching one skilled in theart to employ the present invention in any appropriate system, structureor manner.

One embodiment provides a firearm simulator body 20 which simulates anM-4A1, AR-15, or M-16 rifle. The firearm simulator body 20 includesupper receiver 120 and lower receiver 140. Like a conventional M-16,upper receiver 120 can be pivotally secured to lower receiver 140 by ascrew or pin.

Lower receiver 140 can include a pistol grip 160, a trigger 170 disposedin front of the pistol grip 160, and a selector 450 disposed above thepistol grip 160. A shoulder stock 220 is secured to lower receiver 140.

A barrel assembly 300 is mounted to the front portion of upper receiver120. The barrel assembly 300 includes a barrel 310 which is directlysecured to upper receiver 120. An upper handguard 330 and lowerhandguard 340 are secured to barrel assembly. A front sight block 360 isdisposed around barrel 310.

FIG. 1 is a side view of one embodiment of a firearm training system 10.FIG. 2 is a side view of simulated firearm body 20. FIG. 3 is aperspective view of upper assembly 120. FIG. 4 is an exploded view ofsimulated firearm body 20.

Firearm training system 10 can include a simulated firearm body 20having a linear motor 500 operatively connected to a slider mass 600,and a controller 50 operatively connected to the linear motor 500.

Simulated firearm body 20 can include upper assembly 120 and lowerassembly 140. Upper assembly 120 can include barrel assembly 300, barrel310, along with upper 330 and lower 340 hand guards.

Lower assembly 140 can include stock shoulder stock 220, buffer tube230, and pistol grip 160. Pistol grip 160 can include trigger 170.Cartridge 250 can be detachably connectable to lower assembly 140.

Linear motor 500 can be attached to upper assembly 120 via connectorassembly 700. Connector assembly 700 can include first end 710, secondend 720, connector plates 721 and 722, connector tube 740 having bore750. Connector plate 721 includes fastener openings 730, and connectorplate 722 includes fastener openings 732. FIG. 5 is a perspective viewof one embodiment of a linear motor 500 and sliding mass 600. FIG. 6 isan exploded side view of linear motor 500 and sliding mass 600. FIG. 7is an assembled view of the linear motor 500 and sliding mass 600.

Linear motor 500 includes a plurality 520 of separately controllableenergized coils 521, 522, 523, 524, 525, 526, 527, 528, 529, 530, etc.which electomagnetically interact with the plurality of magnets 640 inmass 600. By controlling the timing, direction of current, and power ofmagnetic attraction of particular magnetic coils in plurality ofseparately controllable magnetic coils 520 movement, acceleration,velocity, and position of mass 600 can be controlled to obtain a desiredmomentum/impulse curve over time which approximates a particular impulsecurve over time for a particular firearm being simulated.

Linear motor 500 can include a mass 600 which is slidably connected tolinear motor 500. Mass 600 can include first end 610, second end 620,and bore 630. A plurality of magnets 640 can be included inside of bore630. Linear motors 500 are conventionally available but have not beenused in simulated firearms for controlling recoil force.

FIG. 8 is a perspective view of one embodiment of a support 700 forlinear motor 500 and sliding mass 600. Support can include first end 710and second end 720.

On first end can be first and second connector flanges 721,722. Firstconnector flange 721 can include a plurality of connector openings 730.Second connector flange 722 can include a plurality of connectoropenings 732. Coming from second end 720 can be tubular section 740having a tubular bore 750. Linear motor 500 can be mounted to support700 via plurality of openings 730 and 732 being connected to pluralityof connector openings 540. After mounting to support 700, linear motor500 can cause sliding mass 600 to controllably move (e.g., slide,accelerate, etc.) inside of and relative to bore 750.

In one embodiment stop 800 can be employed to increase free recoil fromsliding mass 600. A mechanical stop 800 can be employed inside thesimulated firearm body 20 to “rigidly” (i.e., more quickly negativelyaccelerate to zero sliding mass 600 than linear motor 500 is capable of)at the end of allowed length of travel 660. Such quick stop produces anenhanced recoil effect on user 5 by increasing the maximum generatedrecoil force on the user 5. Because linear motor 500 employs a magneticsliding mass 600 with an electromagnetic stator, there is a couplingbetween the two and a corresponding maximum acceleration anddeceleration that the device can achieve. To such limitation, mechanicalstop 800 can be employed. Since linear motor 500 normally brakes slidingmass 500 by reversing the driving magnetic field originally used toaccelerate sliding mass 600 in the opposite direction, such this featureis not required for stopping at the end of the length of travel 660.Instead braking is left up to contact between sliding mass second end620 and mechanical stop first end 810 inside lower assembly 140. Thisallows for much faster breaking times for sliding mass 600 than linearmotor 500 could, with such faster braking or deceleration creatinglarger reactive forces from sliding mass 600 and thus a larger freerecoil value produced by system 10 at this point in time and positionfor sliding mass 600.

In various embodiments, during an emulated firing cycle, linear motor500 can control movement of sliding mass 600 causing sliding mass 600 tocontinue to acceleration until the last 1 percent of the entire strokeof sliding mass 600 as sliding mass 600 moves towards collision withmechanical stop 800. In various embodiments acceleration can beincreased until the last 2, 3, 4, 5, 10, 15, 20, 25, 30, 35, and/40percent of the entire stroke of sliding mass 600 as sliding mass 600moves towards collision with mechanical stop 800. In various embodimentsthe control of increased acceleration can be until the range of any twoof the above referenced percentages percent of the entire stroke ofsliding mass 600 as sliding mass 600 moves towards collision withmechanical stop 800.

In various embodiments, during an emulated firing cycle, linear motor500 can control movement of sliding mass 600 causing sliding mass 600 tocontinue acceleration until 1 millisecond before sliding mass 600collides with mechanical stop 800. In various embodiments accelerationcan be increased until 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18,and/or 20 millisecond before sliding mass 600 collides with mechanicalstop 800. In various embodiments the control of increased accelerationcan be until the range of any two of the above referenced time periodsbefore sliding mass 600 collides with mechanical stop 800.

Simulated firearm body 20 can include a selector switch 450 operativelyconnected to controller 50 for controlling the type of operation firearmtraining system 10. For example, selector switch 450 can have aplurality of modes of simulation such as: (1) safety; (2) semi-automaticfiring mode; (3) fully automatic firing mode; and (4) burst firing mode.

To use firearm training system 10 a user selects the position ofselector switch 450, aims simulated firearm body 20 at a target, andpulls trigger 170. When trigger 170 is pulled, controller 50 will causelinear motor 500 to kinematically control sliding mass 600 to createreactionary forces which will be transmitted to user holding simulatedfirearm body 20. The reactionary forces created by controlling slidingmass 600 can be controlled to be substantially similar in time andamount for particular ammunition being simulated as being fired from thefirearm being simulated.

In one embodiment a time versus force diagram of a particular round ofammunition being fired from a particular firearm to be simulated can beidentified, and controller 50 can be programmed to control linear motor500 to control movement of sliding mass 600 to create substantially thesame forces over time by controlling the acceleration versus time ofsliding mass. Because force is equal to the product of accelerationmultiplied by mass, controlling acceleration versus time also controlsforce versus time.

In one embodiment a plurality of simulation data point sets (such asforce versus time values) can be generated. In one embodiment aparticular type of ammunition can be tested in a firearm to be simulatedand a data set of apparent recoil force versus time can be generated. Inone embodiment a plurality of measurements are taken over a plurality oftimes. In one embodiment a program for linear motor can be created tocause reaction forces of sliding mass 600 to substantially match in bothtime and amplitude such emulated force diagram for a plurality ofpoints. In one embodiment at least 3 points are matched.

In various embodiments at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15,16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, and/or 100simulation point data sets can be substantially matched. In variousembodiments a range of between any two of the above specified number ofsimulation point data sets can be substantially matched.

In one embodiment system 10 can be used to emulate a force versus timecurve that is estimated to occur with a particular firearm firing aparticular size and type of ammunition being simulated.

Recoil can be thought of as the forces that a firearm places on the userfiring the firearm. Such recoil forces are dependant upon the size andconstruction of the firearm, along with the characteristics of thebullet being fired from the firearm. The recoil imposed on a user of thesame firearm can be different when the firearm fires a first type ofammunition compared to a second type of ammunition.

In one embodiment linear motor 500 and sliding mass 600 combined have atotal mass which approximates the mass of the particular firearm beingsimulated. In one embodiment simulated firearm body 20 which includeslinear motor 500 and sliding mass 600 combined have a total mass whichapproximates the mass of the particular firearm being simulated. Invarious embodiments either the linear motor 500 and/or sliding mass 600combined have a total mass (and/or the simulated firearm body 20 whichincludes linear motor 500 and sliding mass 600 combined) have a totalmass which is about 65, 70, 75, 80, 85, 90, 95, and/or 100 percent ofthe mass of the particular firearm being simulated. In variousembodiments a range between any two of the above referenced percentagescan be used.

In one embodiment is provided a substantially balanced simulated firearmbody 20. By locating linear motor 500 in the front portion of simulatedfirearm body 20, better weight balance as well as a more realisticstarting position for the simulated reactive force vector can beachieved. By positioning sliding mass 600 movement in this way, barrel300 weight and center of gravity of simulated firearm body 20 will bemore realistic to user 5 when system 10 is idle and trigger 170 is notbeing pulled. This is due to the starting position of sliding mass 600.In one embodiment barrel 310 material being used in upper assembly 120will not be steel, upper assembly 120 may feel unrealistic to user 5 dueto a change in weight distribution compared to an upper assembly for anactual firearm being simulated. To solve this problem, during theinitial stage of a recoil simulation cycle, a portion of sliding mass600 can rest inside barrel 310. Such portion of sliding mass simulatesthis extra “missing” weight in barrel 310 with the extra weight from thestator of linear motor 500 assisting as well. When user fires system 10,sliding mass 600 moves from barrel 310 towards the rear of simulatedfirearm body 20 and is stopped by stop 800 that is even with thebeginning of the stock. Sliding mass 600 then returns to its initialposition and creates a seamless effect for user 5 that the weightdistribution of the gun “feels” correct when the gun is not being fired.

In different embodiments, the location of linear motor 500 can be movedfrom the hand grip position, such as in stock 220, or farther up intothe receiver if necessary. FIG. 9 is a side view of one embodiment of asimulated firearm body 20. The amount of linear travel of sliding massis 600 is schematically indicated by arrows 660. In this view, theactual position 666 of second end 620 of sliding mass 600 isschematically shown by “time dependent” vertical line 666′″ indicatingthe transient position of second end 620 of sliding mass 600 in lengthof travel 660. Arrow 1320 schematically represents a time dependentrecoil force which is created by time dependent acceleration of slidingmass 600 by linear motor 500. Clip 650 can be removed from sliding mass600 before or after installation of linear motor 500 to allow, ifdesired, during control of sliding mass 600, first and second ends 610,620 of sliding mass 600 to enter plurality of coils 520 of linear motor500 between first and second ends 530,534 of plurality of coils 520.

FIG. 10 is a schematic flow diagram of various operation of thesimulated firearm system shown in FIG. 1. In one embodiment controller50 can be programmed to control linear motor 500 to control kinematicmovement of sliding mass 600 within length of free travel 660 of slidingmass 600 to cause sliding mass to create a desired reactionary forceversus time curve, where such force versus time curve simulates a forceversus time curve of a particular bullet fired in a particular firearmbeing simulated. Linear motor 500, which includes controlled slidingmass 600 along with motor logic controller 504. Motor logic controller504 is operatively connected to controller 50. A power supply 60 (e.g.,24 volts) can be connected to both linear motor's logic controller 504and controller 50. Because of the larger current demand of the linearmotor 500 stator, a separate power supply 60 (e.g., 72 volts) can beconnected to linear motor 500.

Sequencing

FIGS. 11-15 are sequencing side views showing the sliding mass 600 ofthe linear motor 500 at four different positions relative to simulatedfirearm body 20. In one embodiment system 10 is programmed to simulaterecoil for different ammunition types that a user 5 may use in aparticular rifle. Programming of system 10 can be accomplished bymeasuring the force vs. time of an actual round in a particular weaponssystem to be simulated by system 10 and by using the “free recoil”formula to determine the energy produced by the actual firearm system tobe simulated. Once the force vs. time of the actual firearm system to besimulated is known and the free recoil of this actual system is known,then system 10 can be programmed to cause sliding mass 600 to createreactionary forces to substantially match in at least a first pluralityof preselected data points the same or similar force vs. time and freerecoil energy can be delivered to user 5 giving the same perceivedrecoil as the live ammunition fired from the actual firearm beingsimulated.

Accordingly, by changing the stroke distance, velocity, acceleration,and/or deceleration at preselected time intervals or points of slidingmass 600, the reactive recoil force imparted to user 5 from simulatedfirearm body 20 can be controlled. This reactive recoil force can becontrolled to mimic or simulate:

the recoil force generated by a particular type of ammunition round inthe particular firearm being simulated;

the recoil force generated by different types of ammunition rounds inthe particular firearm being simulated; which different types ofammunition rounds may use more gun powder/less gun powder or use ahigher weight bullet/lower weight bullet or some combination of both.

The different types of recoil forces can be simulated by merely havinglinear motor 500 change the dynamic movements of sliding mass 600 overtime. For example if a larger force is desired at a particular point intime during the recoil time period at such particular point in timelinear motor merely increases the instantaneous acceleration of slidingmass 600 to cause such reactionary force.

FIG. 16 is a graph plotting hypothetical recoil force versus time (shownin green with the square tick marts) of a first round of ammunitionalong with force versus time caused by the linear motor kinematicallycontrolling dynamics of the sliding mass (shown in brown with thetriangular tick marks). FIG. 16 can be compared to sequencing FIGS.11-15. At time zero second end 620 of sliding mass 600 is as shown inFIG. 11 at position 666, and has just started to accelerate in theopposite direction of arrow 1300 (causing a reactive force in thedirection of arrow 1300 to be imposed on simulated firearm body 20 anduser holding body 20). Linear motor 500 causes second end 620 of slidingmass 600 to accelerate and move in the opposite direction of arrow 1300until second end 620 reaches position 666′ (shown in FIG. 12) havingcontact with first end 810 of stop 800. Immediately preceding reaching666′ acceleration of sliding mass 600 causes a reactive force in thedirection of arrow 1300 (shown at time 16 milliseconds in FIG. 16 and ina negative reactive force). However, immediate after impact betweensecond end 620 and first end 810, such collision/contact causes anacceleration of sliding mass 600 in the opposite direction of arrow 1310creating a reactive force in the direction 1310 (shown between times 16and 36 milliseconds in FIG. 16 and being a positive reactive force).During this same time period of contact/collision between second end 620and first end 810, linear motor 500 can independently accelerate slidingmass in the opposite direction of arrow 1310 (adding to the reactiveforce 1310 shown in FIG. 12 by force vectors). From times 36 to 66milliseconds on the graph shown in FIG. 16, controller 50 can beprogrammed to cause linear motor 500 to control acceleration of slidingmass 500 to create the desired simulated recoil reactive forces.

FIG. 13 shows second end 620 at position 666″ where linear motor couldcause sliding mass 600 to accelerate to create a reactive force shown at41 milliseconds in FIG. 16. FIG. 14 shows second end 620 at position666′″ where linear motor could cause sliding mass 600 to accelerate tocreate a reactive force shown at 56 milliseconds in FIG. 16. FIG. 15shows second end 620 at starting position 666 for the next recoil cycle.Now between possible 666′″ shown in FIG. 14 to position 666 shown inFIG. 15 linear motor 500 will have to accelerate sliding mass in thedirection of arrow 1330 (to eventually slow and then stop sliding mass600 at position 666 to be ready for the next recoil cycle). However,such slowing acceleration can be controlled to a minimum to minimize theamount of negative reactive force imposed on simulated firearm body 20and user 5. Such negative reactive force is not shown in FIG. 16 and canbe relatively small. In such manner the amplitudes and timing of suchamplitudes of recoil forces experienced by a user firing a particulartype of bullet in a particular firearm can be simulated by programmedkinematics of sliding mass 600 being controlled by linear motor 500.

To simulate multiple firing cycles, the linear motor 500 can controldynamic movement of sliding mass 600 to create repeated force versustime patterns/diagrams of kinematic movement of sliding mass 600 thedesired number of times or cycles.

FIG. 17 is a graph plotting hypothetical recoil force versus time (shownin green with the square tick marts) of a first round of ammunitionalong with force versus time caused by the linear motor kinematicallycontrolling dynamics of the sliding mass (shown in brown with thetriangular tick marks). FIG. 17 shows a different bullet with differentforce versus time curve to be simulated by programmed linear motor 500controlling kinematic movement of sliding mass 600. Additionally, theoverall period of the curve can be different from 66 millisecond and canchange depending of the recoil characteristics of the firearm beingsimulated firing a particular bullet.

The ability of linear motor 500 to create reactive forces with slidingmass 600 is further enhanced by the alternating of the mass of slidingmass 600. In one embodiment the different overall lengths for slidingmass 600 can be used (with the longer length option having a greatermass). With a greater mass for a given acceleration of such mass thereactive force created is found by the formula force equals mass timesacceleration. In various embodiments sliding mass 600 can be 270 mm inlength slider, or can be 350 mm in length, and such optional slidingmasses 600,600′ can be interchanged with linear motor 500 to modify:

The mass of the sliding mass 600. The 270 mm sliding mass 600 has a massof 215 grams and the 350 mm sliding mass 600′ has a mass of 280 grams.The change in mass gives rise to different reactive forces caused byacceleration, and different free recoil energies, which can be used tobetter approximate the force vs. time curve produced by certain roundsof ammunition.

Additionally, the length of sliding mass 600 changes the overallacceleration and length of travel 660 linear motor 500 has toapproximate the force vs. time curve produced by particular rounds ofammunition.

With a shorter sliding mass 600, linear motor 500 can achieve highervelocities due to the longer acceleration time and thus give largervalues of free recoil energy to the user.

The maximum reactive forces for different sliding masses 600,600′ can becomputed as follows:

E _(tgu)=0.5*m _(gu) *v _(gu) ²

since there will be no powder or velocity of the powder charge, thesevalues (v_(c) & m_(c)) go to zero and we have the standard kineticenergy formula K=(0.5*m*v2) . The maximum values achieved for E_(tgu)are as follows for both sliders:

Sliding Mass Sliding Mass Sliding Mass Overall Mass Free Length MassAcceleration of Firearm Recoil 270 mm 215 grams 7.35 m/s² 1.5 kg 2.539 J350 mm 280 grams  7.4 m/s² 1.5 kg 4.071 J

FIGS. 18-21 are schematic sequencing diagrams illustrating an individual5 repetitively firing of a firearm simulating body 20 with recoilcausing increasing loss of accuracy with repetitive shots. In thesefigures is schematically shown a simulating training exercise viasemi-auto-burst fire modes with electronic recoil to training anindividual 5 for accuracy.

One embodiment uses firearm simulating body 20 with linear motor 500simulating an M4A1 rifle firing a particular type of bullet (althoughother types of firearms and bullets are envisioned in differentembodiments). In one embodiment selector switch can have three modes ofoperation (1) semiautomatic 454, (2) burst 456, and (3) fully automatic458. Schematically show in FIGS. 18-21 is a user fire after selectingburst 452 mode. In burst mode (2) a series of three simulated bulletfirings will be performed by system 10.

Individual 5 selects which type of simulation for this particularfirearm is desired by using selector switch 450. As schematically shownin FIG. 18, user 5 aims simulated firearm body 20 at target area 1400.User next pulls on trigger 170 which is connected to trigger switch 172sending a signal to controller 50. Controller 50 controls linear motor500 which in turn controls sliding mass 600. Controller 50 also controlslaser emitter 1200.

Controller 50 causes linear motor 500 causing sliding mass 600 totraverse a pre-programmed kinematic movements creating reactionaryforces in accordance with a predefined reactionary force versus time inan effort to simulate the recoil forces that an individual wouldexperience actually simulating the particular bullet for the particulargun. Controller 50 is also connected to an infrared laser system 1200which can be in phase with user 5 pulling trigger 170.

Laser 1200 simulates on the target screen (area 1400 or 1410) where abullet would have traveled from simulated firearm body 20.

In FIG. 19, the first of the three simulated burst rounds, laser 1200shoots laser line 1220 and has a hit 1221 in target area 1400. In FIG.20, the second of the three simulated burst rounds, laser 1200 shootslaser line 1230 and has a hit 1231 in target area 1400 (but closer tonon-target area 1410). In FIG. 21, the second of the three simulatedburst rounds, laser 1200 shoots laser line 1230 and has a hit 1231 innon-target area 1410.

Arrow 1350 schematically represents the simulated recoil placed on body20 causing user's 5 aim to degrade. With repeated use of system 10, user5 can become accustomed to the simulated recoil and adjust his aim.

In an actual training exercise, the projection system will simulate“target space” and “non-target” space for user 5. If user 5 fires off ofthe screen 1400, this counts as “non-target” space 1410. These targets1400 can be either moving or stationary and may vary greatly in size andshape. However, the projection system will count the total number ofbullet strikes (e.g., 1221, 1231) in target space and non-target spaceand add them. This enables the following formula to be used:

Accuracy=[Total−(non-target space)]/Total]*100% to determine accuracyfor user 5.

For example, if the user fired a total of 10 shots, corresponding to 4shots in the target space 1400 and 6 shots in the non-target space 1410the formula would read:

Accuracy=[[10−6]/10]*100%.

This simulation would give the user an accuracy of 40%. Since a realrecoil effect will be produced and knock the user's sights off of thetarget space 1400 for which he is aiming, system 10 this will help totrain user 5 to become more accurate in firing actual firearm system butwithout the need to fire live ammunition.

Located inside barrel 310 can be laser emitter 1200. A preferred laseremitter assembly is available Laser Shot, located in Stafford, Texas.Laser emitter 1200 assembly includes a circuit board, a battery box, aswitch, and a laser emitter. Laser emitter 1200 is preferably housedwithin barrel 310, and is oriented to emit a laser beam substantiallyparallel to and coaxial with the longitudinal centerline of barrel 310.A typical cyclic rate for full automatic fire with a low cyclic rate isapproximately 600 rounds per minute. A typical cyclic rate for fullautomatic fire at a high cyclic rate is approximately 900 rounds perminute, approximately simulating the cyclic rate of an M-4A1, AR-15,and/or M-16 rifle.

The firearms training simulator therefore simulates the recoil, cyclicrate, configuration, controls, and mode of operation of the firearm forwhich it is intended to be used to train a shooter. The trainingsimulator therefore provides the opportunity to conduct decision-makingtraining scenarios projected on a screen, with the safety and reducedfacilities cost of using a laser instead of live ammunition, whileduplicating a sufficient number of the characteristics of a conventionalfirearm so that the training will effectively carry over to aconventional firearm.

FIG. 22 is a perspective view of another embodiment of a linear motor500 and sliding mass 600. Linear motor 500 can include sensors 550 and552, which can be Hall Effect sensors. FIG. 23 is a perspective view ofa sliding mass 600 with exemplary plurality of magnets 640 removed. FIG.24 is an enlarged perspective view of the sliding mass 600 withexemplary magnets 640. In FIGS. 23 and 24 the plurality of magnets 640(e.g., magnets 642, 644, 646, etc.) can be comprised of neodymium.Additionally, between pairs of magnets 640 can be spacers (e.g., spacer643 between magnets 642 and 644, and spacer 645 between magnets 644 and645). In a preferred embodiment the spacers can be comprised of iron(such as ferromagnetic iron). In a preferred embodiment plurality ofmagnets 640 are aligned so that like poles are facing like poles (i.e.,north pole to north pole and south pole to south pole). In FIGS. 23 and24, starting from the left hand side, magnet's 642 pole to the left isnorth and pole to the right is south, and magnet's 644 pole to the leftis south and pole to the right is north.

Thus, the plurality of magnets 640 contained in slider/driven mass 600have similar poles facing each other creating a repelling force. In apreferred embodiment the outer shell of sliding mass 600 longitudinallyholds the plurality of magnets 640 and spacers securely together. Inpreferred embodiment the outer shell can be stainless steel which can benon-magnetic of a material that does not substantially interfere withthe magnetic forces between plurality of coils 520 of linear motor 500and plurality of magnets 640 of sliding mass 600.

FIGS. 25-29 schematically show operation of linear motor 500 and slidingmass 600 as the plurality of magnets 640 are driven by the plurality ofcoils 520. FIG. 25 is a schematic diagram illustrating operation of theplurality of coils 520 in a linear motor 500. FIGS. 26 and 27 areschematic diagrams illustrating operation of the coils 520 in a linearmotor 500 in two different energized states.

In FIG. 25, coils 521, 523, and 525 in the stator of linear motor 500can be wired in series and labeled as phase 1 (when wired together inseries these coils of phase 1 can be considered sub-coils of a singleindependently controllable magnetic coil). Coils 522 and 524 are alsowired in series and are labeled as phase 2 (when wired together inseries these coils of phase 2 can be considered sub-coils of a singleindependently controllable magnetic coil). The plurality independentlycontrollable magnetic coils 520 of linear motor 500 can be wound in thesame or different direction depending on design.

Each independently controllable coil in phase 1 and 2 produces its ownmagnetic field when energized. This allows for independentlycontrollable magnetic coils of phase 1 and 2 the plurality of coils 520to repel each other or for phase 1 and phase 2 coils to attract eachother depending on the way the phases are polarized and the coils wound.These alternative states of polarization are shown in FIGS. 26 and 27.In FIG. 26 phase 1 and phase 2 are polarized in the same direction sothat coils in the two phases are attracted to each other. In FIG. 27phase 1 and phase 2 are polarized in the opposite direction so thatcoils in the two phases repel to each other. It can be seen that byvarying the polarization of phases in the plurality of independentlycontrollable magnetic coils 520 of linear motor 500, sliding mass 600can be controllably moved as desired through the plurality of coils 520so as to create the desired reactive forces user 5 such as timedependently controlled force, acceleration, velocity, position, and/ormomentum; or overall impulse.

FIGS. 28 and 29 are schematic diagrams illustrating movement of theplurality of magnets 640 of sliding mass 600 through the plurality ofcoils 520 a linear motor 520 in different energized states.

FIG. 28 schematically indicates initial movement of sliding mass 600with plurality magnets 640 through plurality of coils 520 of linearmotor 500. In FIG. 28, the first magnet 642 of sliding mass 600 entersplurality of coils 520 of linear motor 500. Plurality of coils 520 canthen be energized with phase 2 polarized as shown and phase 1 not beingenergized (or OFF). This causes magnet 642 (and sliding mass 600) to bepulled deeper into plurality of coils (schematically indicating by thearrow towards the right). As schematically shown in FIG. 29, when firstmagnet 642 moves halfway into coil 522, phase 1 can be energized (orturned ON) creating a pulling force on magnet 642 and speeds the secondmagnet 644 to the center of coil 521 while at the same time repellingthe magnet 642. The movement of sliding mass 600 eventually stops whenthe plurality of magnets 640 reach steady state with the plurality ofcoils 520, which in this case means that the north pole of coils 521 and522 are respectively aligned with the north poles of magnets 642 and644; and coil 522 is aligned with magnet 644′s south pole and coil 521is aligned with the magnet 644′s south pole. Thus, the magnetic forcesare in equilibrium and movement ceases while phase 1 and 2 remainenergized with this polarization. So, by switching the coils ON/OFF andby alternating the coils polarization the slider (filled with neodymiummagnets) can be pushed or pulled through the stator (made up of manycoils). Furthermore, the number of coils depicted in FIGS. 25 through 29through can be increased to have a larger accelerating cross section.

The velocity, acceleration, and linear distance of sliding mass 600 canbe measured as a function of Hall Effect sensors 550 and 552 that are 90degrees out of phase. Out of phase Hall Effect sensors 550 and 552 caneach produce a linear voltage in response to increasing or decreasingmagnetic field increases. FIG. 22 can show the mechanical alignment inlinear motor 5000 and sensors 550,552. The response that sensors 550 and552 give as a function of magnetic field strength (flux through thesensor) versus voltage (out of the sensor) is depicted in FIG. 30, whichis a diagram illustrating magnetic flux density versus voltage output.

FIGS. 31 and 32 are exemplar diagrams of sensor 550 and 552 voltageresponse versus time for a slider moving through the linear motor. Whensliding mass 600 is moved through the plurality of coils 520 of linearmotor 500, 90 degree out of phasesensors 550 and 552 provide a voltageresponse versus time falling into a Sine or Cosine function as indicatedin FIGS. 31 (sine(x) for sensor 550) and FIG. 32 (cosine(x) for sensor552). These resultant waves are generated by sensors 550 and 552 becausegenerated magnetic flux for the plurality of magnets 640 inside slidingmass 500 are most powerful at their magnetic poles. So as the northpoles of two magnets approach, the wave goes positive and peaks whendirectly above those poles. Continuing in the same direction, as thesouth poles approach, the wave goes negative and peaks when directlyabove those poles. Thus, one sensor 550 gives a function of Sin(x) andthe other sensor 552 gives a function of Cos(x). As can be seen thesefunctions are 90 degrees out of phase. Two sensors 550 and 552 are usedfor better precision feedback and control of sliding mass 600 throughthe plurality of coils 520 of linear motor 500, and as a method to makesure sliding mass is continually tracked accurately.

To provide additional explanation, sensor 550 generating a sin wave isplotted in FIG. 31, and will be further examined regarding how thisgraph can be used to track velocity, acceleration, and displacement ofsliding mass 600. FIG. 33 is a diagram of a sample wave form whichillustrates the various components of a wave form generated by sensor550. The wavelength (λ) relates to the velocity of sliding mass 600through plurality of coils 520 of linear motor 500. As the wavelengthshortens, the frequency can be calculated by f=1/λ, and the frequencywill increase as the wavelength shortens.

FIGS. 34 and 35 are exemplar diagrams of sensor voltage response versustime for a sliding mass 600 moving through the linear motor 500 at twodifferent constant linear speeds. For example, in FIG. 34 sliding mass600 can be said to be moving through plurality of coils 520 at 1 meterper second and generating this wave. As sliding mass 600 speeds up to 2meters per second, FIG. 35 is generated. It can be seen that thisincrease in wave frequency corresponds to the velocity with whichsliding mass 600 is moving through the plurality of coils 520 of linearmotor 500. Furthermore, the change in waveform from FIG. 34 to FIG. 35relates to the acceleration of sliding mass 600. FIGS. 34 and 35 eachindividually represent constant velocities of sliding mass 600 (althoughthe constant velocity in FIG. 35 is twice that of the constant velocityin FIG. 34) so that in each of these two figures, there is noacceleration; however, as sliding mass 600 slider approached 2 metersper second linear speed shown in FIG. 35, the frequency increased to thevalue in FIG. 35: that frequency change over time can be used to computeacceleration of driven mass 600. Lastly, distance traveled by drivenmass 600 can be calculated by knowing the length of the plurality ofmagnets 640 in sliding mass, and counting the number of wavelengths thatgo past sensor 550. Each wavelength corresponds to the full length ofthe permanent magnet inside the body of sliding mass 600. Accordingly,velocity, acceleration, and distance can be calculated from sensors 550,552 voltage versus magnetic flux graphs.

Emulating Overall Recoil Impulse

In one embodiment linear motor 500 and sliding mass 600 can be used toemulate total recoil impulse for a particular firearm firing aparticular form of ammunition. “Actual recoil force” is the forcegenerated by a particular type of firearm firing a particular type ofammunition at any point in time after firing where such force istransmitting to the user. Such actual recoil force can be plotted over aparticular period of time from initial firing of the ammunition in thefirearm to the end of any actual recoil force following such firing.

On the other hand, “generated recoil force” is the reactive forcegenerated by linear motor 500 controlling movement of sliding mass 600.Such generated recoil force will be transmitted to a user 5 holdingsimulated firearm body 20 of simulator system 10.

Actual recoil impulse is the area under a force versus time diagramwhere the force is generated by a particular type of firearm firing aparticular type of ammunition. Generated recoil impulse is the areaunder a force versus time diagram 1600 of a reactive force generated bylinear motor 500 controlling movement of sliding mass 600 (e.g.,acceleration, velocity, and distance) over time.

FIG. 16 shows prophetic examples of diagrams for actual recoil force1500 versus time, along with generated recoil force 1600 versus time.The area under the actual recoil force versus time diagram 1500 is theactual recoil impulse. The area under the generated recoil force versustime diagram 1600 is the generated recoil impulse. Note how the areaunder the generated recoil impulse can be both positive (above thezero), and negative (below the zero). In a preferred embodiment thenegative area would be subtracted from the positive area in calculatingtotal impulse. In other embodiments the negative area can be ignored incalculating total impulse.

In these two diagrams the force versus time diagrams 1500, 1600 ofactual recoil over time versus reaction forces generated by linear motor500 and sliding mass 600 over time closely track each other so that theimpulse and reactive impulse are approximately equal. However, indifferent embodiments the actual recoil over time diagram 1500 versusreaction forces generated by linear motor 500 and sliding mass over time1600 can substantially vary as long as both calculated impulses (fromthe areas under the diagrams) are close to each other at the end of thefiring cycle.

FIG. 36 shows a single diagram with three force versus time plots: (1)force versus time of actual forces 1500 (first plot for an M16/AR-15type rifle firing a 0.223 Remington bullet/round having an overallweight of about 7.5 pounds), and (2) force versus time of generatedreactive forces from linear motor and sliding mass in combination with amechanical stop 1600, and (3) force versus time of generated reactiveforces from linear motor and sliding mass without using a mechanicalstop 1600′. A positive value of force indicates that a force pushinguser 5 backward. As can be seen by the time, a firing cycle of about 90milliseconds is used.

Diagram 1600 includes a spike 1610 when the slider 600 hits themechanical stop 800, and the areas under each plot 1500, 1600 should beroughly the same to get the same overall impulse. For diagram 1600, time1700 indicates the initial contact between sliding mass 600 andmechanical stop 800. In different embodiments, because the time periodfor the collision between sliding mass 600 and mechanical stop 800 is soshort (about less than 5 milliseconds), time of initial contact 1700 canalso be calculated using the time of peak reactive force 1620.

In FIG. 36 is shown the peak 1520 of actual recoil force 1500 which iscompared to the peak 1620 of generated recoil force 1600, and thedifference 1630 between such peaks. In various embodiments mechanicalstop 800 can be used to generate a spike 1610 in the generated recoilforce which spike 1620 has a difference of 1630 compared to the peak1520 of actual recoil force 1500.

In various embodiments peak 1620 can be such that the difference 1630can be minimized. In various embodiments, during an emulated firingsequence, the difference 1630 is less than 50 percent of the peak 1620.In various other embodiments the difference 1630 is less than no morethan 45, 40, 35, 30, 25, 20, 15, 10, 5, 4, 3, 2, and/or 1 percent of thepeak 1620. In various embodiments the difference 1630 can be withinrange between any two of the above referenced percentages peak 1620.

In various embodiments, the average generated recoil force by linearmotor 500 controlling slider 600 during a particular simulated firingsequence before initial contact of sliding mass 600 with mechanical stop800 at time 1700 can be calculated by calculating the impulse up toinitial impact at time 1700 divided by the time at time 1700. In variousembodiments the peak 1620 of generated reactive force is at least 50percent greater than the average generated recoil force by linear motor500 controlling slider 600 during a particular simulated firing sequencebefore initial contact of sliding mass 600 with mechanical stop 800 attime 1700. In various embodiments the peak generated reactive force 1620is greater than 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130,140, 150, 175, 200, 225, 250, 275, 300, 400, 500, 600, 700, 800, 900,1000, 1200, 1500, and/or 2000 percent greater than the average generatedrecoil force by linear motor 500 controlling slider 600 during aparticular simulated firing sequence before initial contact of slidingmass 600 with mechanical stop 800 at time 1700. In various embodiments arange between any two of the above referenced percentages can be usedfor such comparison.

In various embodiments, the average generated recoil force by linearmotor 500 controlling slider 600 during an entire particular simulatedfiring sequence can be calculated by calculating the impulse during theentire firing sequence and dividing the time for such entire firingsequence. In various embodiments the peak 1620 of generated reactiveforce is at least 50 percent greater than the average generated recoilforce by linear motor 500 controlling slider 600 during an entireparticular simulated firing sequence (i.e., both before and afterinitial contact of sliding mass 600 with mechanical stop 800 at time1700). In various embodiments the peak generated reactive force isgreater than 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130,140, 150, 175, 200, 225, 250, 275, 300, 400, 500, 600, 700, 800, 900,1000, 1200, 1500, and/or 2000 percent greater than the average generatedrecoil force by linear motor 500 controlling slider 600 during an entireparticular simulated firing sequence. In various embodiments a rangebetween any two of the above referenced percentages can be used for suchcomparison.

In various embodiments, the average generated recoil force by linearmotor 500 controlling slider 600 during a particular simulated firingsequence after initial contact of sliding mass 600 with mechanical stop800 at time 1700 can be calculated by calculating the impulse followinginitial impact at time 1700 divided by the time following time 1700. Invarious embodiments the peak 1620 of generated reactive force is atleast 50 percent greater than the average generated recoil force bylinear motor 500 controlling slider 600 during a particular simulatedfiring sequence subsequent initial contact of sliding mass 600 withmechanical stop 800 at time 1700. In various embodiments the peakgenerated reactive force is greater than 55, 60, 65, 70, 75, 80, 85, 90,95, 100, 110, 120, 130, 140, 150, 175, 200, 225, 250, 275, 300, 400,500, 600, 700, 800, 900, 1000, 1200, 1500, and/or 2000 percent greaterthan the average generated recoil force by linear motor 500 controllingslider 600 during a particular simulated firing sequence subsequent toinitial contact of sliding mass 600 with mechanical stop 800 at time1700. In various embodiments a range between any two of the abovereferenced percentages can be used for such comparison.

FIG. 37 is an exemplar diagrams 1502, 1602, 1602′ of an accelerationversus time plotted for recoil acceleration for an actual firearm 1502,compared to simulated acceleration of the sliding mass caused by themethod and apparatus using a mechanical stop 1602, and not using amechanical stop 1602′. Force from the acceleration diagrams can becalculated using the formula force equals mass times acceleration.

FIG. 38 is an exemplar diagrams 1504, 1604, 1604′ of a velocity versustime plotted for recoil velocity for an actual firearm 1504, compared tosimulated velocity of the sliding mass caused by the method andapparatus using a mechanical stop 1604, and not using a mechanical stop1604′.

In one embodiment stop 800 can be employed to modify the generatedrecoil force diagram from linear motor 500 controlling sliding mass 600by sharply increasing the reactive force at the point of collisionbetween sliding mass 600 and mechanical stop 800. A mechanical stop 800can be employed inside the simulated firearm body 20 to “rigidly” (i.e.,more quickly negatively accelerate to zero sliding mass 600 than linearmotor 500 is capable of) at the end of allowed length of travel 660.Such quick stop produces an enhanced recoil effect on user 5, and highergenerated reactive force. In one embodiment, the reactive forcegenerated by sliding mass 600 colliding with mechanical stop 800 isgreater than any force generated by linear motor 500 acceleratingsliding mass 600 during an emulated firing sequence.

In various embodiments, during an emulated firing sequence, the maximumreactive force generated by linear motor 500 accelerating sliding mass600 is no more than 50 percent of the reactive force generated bysliding mass 600 colliding with mechanical stop 800. In various otherembodiments the maximum reactive force generated by linear motor 500accelerating sliding mass 600 is no more than 55, 60, 65, 70, 75, 80,85, 90, 95, 99, and/or 100 percent of the reactive force generated bysliding mass 600 colliding with mechanical stop 800. In variousembodiments the maximum reactive force generated by linear motor 500accelerating sliding mass 600 can be within range between any two of theabove referenced percentages of the maximum reactive force generated bylinear motor 500 controlling sliding mass 600.

In various embodiments either actual recoil impulse and/or the generatedrecoil impulse by linear motor 500 controlling sliding mass 600 arewithin about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and/or 100 percentof each other. In various embodiments a range between any two of theabove referenced percentages can be used.

In various embodiments the total time for an emulated firing cycle bylinear motor 500 controlling sliding mass 600 can be less than about 200milliseconds. In various embodiments the maxim time for an emulatedfiring cycle can be less than about 25, 30, 35, 40, 45, 50, 55, 60, 65,70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180,190, and/or 200 milliseconds. In various embodiments the maximum timecan be between any two of the above referenced times.

Emulating a Force Versus Time Plot of Firearm

In one embodiment an actual firearm with actual ammunition can be testedand the actual recoil force over time plotted. In this embodiment linearmotor 500 and magnetic mass/shaft 600 movement (e.g., acceleration,velocity, and position) can be programmed so as to emulate the actualforce versus time diagram that was obtained from test. In differentembodiments the emulated force versus time can be within 1, 2, 3, 4, 5,10, 15, 20, 25, 30, 35, 40, 45, and/or 50 percent of the plot. Indifferent embodiments the variation can be within a range between anytwo of the above referenced values. In different embodiments totalimpulse (which is the integral or sum of the area under the force versustime diagram) can be emulated for relatively short time sequences as itis believe that users have difficulty perceiving changes in force overtime for very short time intervals regarding recoil forces, andeffectively feel the overall impulse of the recoil force in firearms.

Changing the Strength of the Magnetic Field of Linear Motor

In one embodiment, the strength of the magnetic field generated by theplurality of coils 520 of linear motor 500 as a magnet in magneticmass/shaft 600 passes by and/or is in touch with a particular coilgenerating a magnetic field can be increased from an initial value. Indifferent embodiments the strength of the field can be changed by 1, 2,3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, and/or 50 percent of theinitial value. In different embodiments the variation can be within arange between any two of the above referenced percentages.

Using Sensors To Directly/Indirectly Measure Dynamic Properties ofSliding Mass and Have Linear Motor Control Dynamic Properties of SlidingMass Based on Sensor Input

In one embodiment, the acceleration, velocity, and/or position versustime of the magnetic mass/shaft 600 can be measured directly and/orindirectly (such as by sensors 550 and/or 552), and linear motor 500 canchange/set the strength of the magnetic field generated by plurality ofcoils 520 to achieve a predetermined value of acceleration, velocity,and/or position versus time for sliding mass 600. In differentembodiments the predetermined values of emulated acceleration, velocity,and/or position versus time can be based on emulating a force versustime diagram obtained from testing an actual firearm (or emulatingimpulse). In different embodiments the emulated diagram can be within 1,2, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, and/or 50 percent of theplot. In different embodiments the variation can be within a rangebetween any two of the above referenced values.

Options to Program in Different Variations for Firearm to be Simulated

In various embodiments, a user of system 10 is provided one or more ofthe following options in using system 10 regarding changes in a type offirearm for which recoil is to be simulated by system 10.

-   -   a) different size/caliber/type of ammunition in actual type of        firearm to be simulated with particular type of ammunition.    -   b) adding/removing a muzzle suppressor to actual type of firearm        to be simulated with particular type of ammunition.    -   c) different size/type of bolt springs for actual type of        firearm to be simulated with particular type of ammunition.

In each of the above options system 10 causes linear motor 500 tocontrol sliding mass 600 to generate a recoil force versus time diagram(or generate an impulse) which is different from the simulation for thetype of firearm without the option selected, and which approximates therecoil of the firearm having such option.

Using Same Core Simulation System with Different Firearm ModelAttachments to Provide User with Option of Better Simulating DifferentTypes of Firearms

Same core simulation system but having different firearm attachments forsimulating different firearms. Here, using the same controller 50 andattached linear motor 500, have different firearm attachments (e.g.,AR-15 rifle unit attachment, and Glock pistol unit attachment). Here themagnetic mass/shaft 600 slidably connected to the linear motor 500 canalso be changed but keep same linear motor 500.

In various embodiments simulator 10 can include a plurality of differentbody attachments 20, 20′, 20″, etc. for simulating recoil patterns froma plurality of different type firearms, each of the plurality of bodyattachments being interchangeably operably connectable with linear motor500. In various embodiments, each of the plurality of body attachments20, 20′, 20″, etc. can include unique identifiers that inform controller50 in the selection of one of a plurality of predefined sets of recoilsimulating kinematic movements of sliding mass 600 in order to simulatea recoil pattern for the particular type of firearm that the particularbody attachment represents. Based on the unique identifier of theparticular body attachment 20, 20′, 20″, etc, operably connectable tolinear motor, controller 50 can select one of the plurality ofpredefined sets of kinematic movement to control linear motor 500 incontrolling sliding mass 600 to create a series of predefined movementsfor sliding mass 600 and emulate recoil for the particular type offirearm that the particular connected body attachment represents. Invarious embodiments the individual identifiers can be microcontrollerswhich, when a body attachment 20 is connected to linear motor 500,communicate with microcontroller 50 (shown in FIG. 10), and identify theparticular type of firearm for which recoil is to be simulated. In oneembodiment the plurality of interchangeable different type bodyattachments 20, 20′, 20″, etc. includes at a plurality of different typerifles. In one embodiment the plurality of interchangeable differenttype body attachments 20, 20′, 20″, etc. includes at a plurality ofdifferent type shotguns. In one embodiment the plurality ofinterchangeable different type body attachments 20, 20′, 20″, etc.includes at least one rifle body type and at least one shotgun body typeand/or at least one pistol body type. In one embodiment the plurality ofinterchangeable different type body attachments 20, 20′, 20″, etc.includes a plurality of different type rifles and different typeshotguns and/or pistols.

As to a further discussion of the manner of usage and operation of thepresent invention, the same should be apparent from the abovedescription. Accordingly, no further discussion relating to the mannerof usage and operation will be provided.

The following is a list of reference numerals:

LIST FOR REFERENCE NUMERALS

-   (Reference No.) (Description)-   5 user-   10 firearm training simulator system-   20 simulated firearm body-   50 controller-   54 connecting wire bus-   60 power supply or supplies-   100 receiver-   120 upper receiver-   140 lower receiver-   160 pistol grip-   170 trigger-   172 trigger switch-   180 charging handle-   200 sight rail-   210 rear sight-   220 shoulder stock-   230 buffer tube-   250 cartridge-   254 cartridge release-   280 the adjustment lever-   300 barrel assembly-   310 barrel-   320 barrel bore-   330 upper handguard-   340 lower handguard-   350 rail-   360 front sight-   370 flash hider-   400 bolt-   450 selector interface switch-   452 off position-   454 semi automatic position-   456 burst position-   458 fully automatic position-   500 linear motor-   504 linear motor logic controller-   510 driving portion-   520 plurality of controllable energized coils-   521 controllable coil-   522 controllable coil-   523 controllable coil-   524 controllable coil-   525 controllable coil-   526 controllable coil-   530 first end of plurality of coils-   534 second end of plurality of coils-   540 fastener openings-   550 sensor-   552 sensor-   600 driven mass-   610 first end-   620 second end-   630 bore-   640 plurality of magnets-   641 spacer-   642 magnet-   643 spacer-   644 magnet-   645 spacer-   646 magnet-   650 stop-   660 length of travel for driven mass-   666 position of second end of driven mass with respect to length of    travel-   700 support for linear motor-   710 first end-   720 second end-   721 first connector flange-   722 second connector flange-   730 openings-   732 openings-   740 tubular section-   750 bore-   800 stop-   810 first end-   820 second end-   1000 trigger switch-   1100 clip switch-   1200 laser emitter-   1210 wires-   1220 first laser path-   1221 location of hit for first laser path-   1230 second laser path-   1231 location of hit for second laser path-   1240 third laser path-   1241 location of hit for third laser path-   1300 arrow-   1310 arrow-   1320 arrow-   1330 arrow-   1350 arrow-   1400 target area-   1410 non-target area-   1500 actual recoil force diagram-   1502 actual acceleration diagram-   1504 actual position diagram-   1520 peak actual recoil force-   1522 value of peak recoil force-   1600 simulated recoil force diagram-   1602 simulated acceleration diagram-   1604 simulated position diagram-   1610 spike in force diagram caused by mechanical stop-   1620 peak force-   1630 difference between peak actual recoil force and peak generated    recoil force-   1700 time at which slider first impacts mechanical stop

It will be understood that each of the elements described above, or twoor more together may also find a useful application in other types ofmethods differing from the type described above. Without furtheranalysis, the foregoing will so fully reveal the gist of the presentinvention that others can, by applying current knowledge, readily adaptit for various applications without omitting features that, from thestandpoint of prior art, fairly constitute essential characteristics ofthe generic or specific aspects of this invention set forth in theappended claims. The foregoing embodiments are presented by way ofexample only; the scope of the present invention is to be limited onlyby the following claims.

1. A system, comprising: a body; a linear motor having a sliding mass,the linear motor attached to the body and configured to control movementof the sliding mass the thereby generate a force on the body; a sensorconfigured to measure motion of the sliding mass; and a controllerconfigured to receive signals from the sensor and to control the motionof the sliding mass based on the received signals from the sensor. 2.The system of claim 1, wherein the sensor is configured to generate asignal representing one or more of a velocity, an acceleration, and alinear position of the sliding mass.
 3. The system of claim 1, whereinthe linear motor further comprises: two or more magnetic coils thatgenerate a time dependent magnetic field when electrical currents aredriven through the magnetic coils by the controller; and wherein thesliding mass includes two or more magnets that magnetically interactwith the magnetic field generated by the magnetic coils to therebygenerate a force on the sliding mass which causes movement of thesliding mass.
 4. The system of claim 3, wherein the sensor is configuredto measure magnetic field fluctuations arising due to motion of magnetsassociated with the sliding mass, and wherein the controller is furtherconfigured to determine position, velocity, and acceleration, of thesliding mass based on the measured magnetic field fluctuations.
 5. Thesystem of claim 4, wherein the sensor includes one or more Hall Effectsensors.
 6. The system of claim 5, wherein the sensor includes two HallEffect sensors that are configured to be 90 degrees out of phaserelative to one another.
 7. The system of claim 4, wherein thecontroller is configured to determine one or more of position, velocity,and acceleration of the sliding mass, wherein the velocity is determinedbased on a measured frequency of magnetic field fluctuations,acceleration is based on changes in frequency of magnetic fieldfluctuations, and position is based on counting periods of magneticfield fluctuations.
 8. The system of claim 3, wherein the controller isconfigured to set or change a strength of magnetic fields generated bythe magnetic coils, in response to signals received from the sensor, tothereby achieve a predetermined value of acceleration, velocity, and/orposition of the sliding mass versus time.
 9. The system of claim 8,wherein the controller is configured to change a magnetic field strengthby one of a plurality of percentages of an initial value, or to changethe magnetic field strength in a range between any two of the pluralityof percentages, the plurality of percentages including 1, 2, 3, 4, 5,10, 15, 20, 25, 30, 35, 40, 45, and/or 50 percent.
 10. The system ofclaim 3, wherein the sliding mass includes a plurality of permanentmagnets linearly aligned adjacent each other with like poles facing likepoles.
 11. The system of claim 10, further comprising a plurality ofindependently controllable magnetic coils which are longitudinallyaligned, and wherein the controller is configured to simultaneouslyenergy adjacent independently controllable magnetic coils to therebygenerate oppositely polarized magnetic fields.
 12. The system of claim11, wherein the linear motor is configured to cause movement of thesliding mass by varying current through individual independentlycontrollable coils in relation to a proximity of a particular magnet inthe plurality of magnets, of the sliding mass, to a particular coil inthe plurality of independently controllable magnetic coils.
 13. Ansystem, comprising: a body; a linear motor attached to the body, thelinear motor having a sliding mass and two or more independentlycontrollable magnetic coils which are magnetically coupled to thesliding mass; and a controller that controls movement of the slidingmass by controlling a current in one or more magnetic coils of thelinear motor such that the sliding mass produces a force on the body,the force having a predetermined time dependence.
 14. The system ofclaim 13, wherein the body is configured as a firearm body and thecontroller is configured to control the linear motor to generate forceson the firearm body to simulate a recoil pattern of an actual firearm.15. The system of claim 14, wherein the body is configured as one of aplurality of interchangeable firearm bodies such that the system may bereconfigured to simulate recoil patterns of a plurality of differenttypes of firearms.
 16. The system of claim 15, wherein the body includesa unique identifier that is configured to inform the controller that thebody corresponds to one of the plurality of predetermined types offirearms, and wherein the controller is configured to recognize theidentifier and to generate a corresponding one of a predefined set ofrecoil simulating kinematic movements to thereby simulate the recoilpattern of the actual firearm corresponding to the type of firearmrepresented by the body.
 17. The system of claim 13, wherein thecontroller is configured to control the linear motor to impart to thesliding mass a time dependent force that differs from a time dependentforce of an actual firearm, but has a recoil impulse substantially equalto an impulse associated with the time dependent force of the actualfirearm.
 18. The system of claim 13, wherein the controller isconfigured to control the linear motor to impart to the sliding mass atime depenent force that includes a braking force that decelerates thesliding mass.
 19. The system of claim 13, further comprising: a sensorconfigured to measure motion of the sliding mass; and wherein thecontroller is configured to receive signals from the sensor and tocontrol the motion of the sliding mass based on the received signalsfrom the sensor.
 20. The system of claim 19, wherein the sliding massincludes two or more magnets that magnetically interact with themagnetic field generated by the two or more magnetic coils to therebygenerate a force on the sliding mass which causes movement of thesliding mass, wherein the sensor is configured to measure magnetic fieldfluctuations arising due to motion of magnets associated with thesliding mass, and wherein the controller is further configured todetermine position, velocity, and acceleration, of the sliding massbased on the measured magnetic field fluctuations.
 21. A method ofcontrolling a system including a body, a linear motor having a slidingmass, the linear motor attached to the body, the method comprising:controlling, using a controller, the linear motor to generate a force onthe sliding mass to thereby generate motion of the sliding mass;measuring motion of the sliding mass using a sensor; receiving, by thecontroller, signals from the sensor; and controlling the motion of thesliding mass based on the received signals from the sensor.
 22. Themethod of claim 21, wherein controlling the linear motor furthercomprises: controlling, by the controller, time dependent currents intwo or more magnetic coils of the linear motor to generate magneticfields, the generated magnetic fields magnetically interacting with twoor more magnets of the sliding mass to thereby generate a force on thesliding mass which causes movement of the sliding mass.
 23. The methodof claim 22, wherein measuring motion further comprises: measuring, bythe sensor, magnetic field fluctuations arising due to motion of magnetsassociated with the sliding mass; and determining, by the controller,time dependent values of one or more of position, velocity, andacceleration, of the sliding mass based on the measured magnetic fieldfluctuations.
 24. The method of claim 23, further comprising:determining velocity based on a measured frequency of magnetic fieldfluctuations; determining acceleration based on changes in frequency ofmagnetic field fluctuations; and/or determining position based oncounting periods of magnetic field fluctuations.
 25. The method of claim21, further comprising: setting or changing, by the controller, astrength of magnetic fields generated by the magnetic coils, in responseto signals received from the sensor, to thereby achieve a predeterminedvalue of acceleration, velocity, and/or position of the sliding massversus time.
 26. The method of claim 25, further comprising: changing,by the controller, a magnetic field strength by one of a plurality ofpercentages of an initial value, or changing the magnetic field strengthin a range between any two of the plurality of percentages, theplurality of percentages including 1, 2, 3, 4, 5, 10, 15, 20, 25, 30,35, 40, 45, and/or 50 percent.
 27. The method of claim 21, wherein thebody is configured as a firearm body, the method further comprising:controlling the motion of the sliding mass to generate a predeterminedtime dependent force corresponding to a time depenent force of a recoilpattern of an actual firearm corresponding to a firearm represented bythe firearm body.
 28. The method of claim 21, wherein the body isconfigured as a firearm body, the method further comprising: controllingthe linear motor to impart to the sliding mass a time dependent forcethat differs from a time dependent force of an actual firearm, but has arecoil impulse substantially equal to an impulse associated with a timedependent force of a recoil pattern of an actual firearm correspondingto a firearm represented by the firearm body.
 29. The method of claim21, further comprising: controlling the linear motor to impart to thesliding mass a time depenent force that includes a braking force thatdecelerates the sliding mass.
 30. The method of claim 22, whereincontrolling the linear motor further comprises: controlling, by thecontroller, current through individual independently controllablemagnetic coils of the linear motor in relation to a proximity of aparticular magnet of the sliding mass to a particular coil in the two ormore independently controllable magnetic coils, to thereby causemovement of the sliding mass.